KR20080108244A - Session control system, session control method, and mobile terminal - Google Patents

Abstract

[PROBLEMS] Mobile communication enabling continuation of TCP communication while maintaining the quality in a real-time communication. [MEANS FOR SOLVING PROBLEMS] A mobile terminal (3a) comprises an application executing section (39) for executing a data transmitting/receiving application, a quality monitoring section (38) for detecting the quality of communication such as of a radio LAN (4), an address control section (31) for making it enable to provide either or both of a fixed address and a care-of address to the application as an receiving address for the data transmission/reception depending on the type of the application being executed by the application executing section (39) and the result of the detection t by the quality monitoring section (38), and a network selection switching section (33) for selecting a communication channel via a home agent when the fixed address is selected as the receiving address and for selecting a communication channel not via the home agent when the care-of address is selected. ® KIPO & WIPO 2009

Description

Session control system, session control method and mobile terminal device {Session Control System, Session Control Method, and Mobile Terminal}

The present invention relates to a session control system, a session control method and a mobile terminal apparatus of IP mobility and real-time communication in mobile communication.

In recent years, IP (Internet Protocol) of mobile communication is progressing, and the case of carrying out Transmission Control Protocol (TCP) communication also in this mobile communication is increasing. In mobile communication, the IP address changes when the terminal moves between access networks, but in TCP communication, the session is disconnected when the IP address changes. Therefore, IP mobility functions such as Mobile IP (MIP) are used to continue TCP communication. Is common. For example, the IETF (Internet Engineering Task Force) proposes standardization of Mobile IPv6 as a specification of the IP mobility (see Patent Document 1, for example).

In the above IP mobility, as illustrated in FIG. 14, the mobile terminal device (MN) 3a does not depend on the position of the mobile terminal device and does not change even when the mobile terminal device moves. A home address (HoA), which is an IP address, is given. This HoA is a fixed IP address on the packet core network 2 which is the network (home link) to which the mobile terminal device 3a originally belongs. In FIG. 14, the wireless LAN 4 and the cellular packet network 6 are connected to the packet core network 2 via another router device 7 or gateway device 5 as another network, and the mobile terminal device 3a is connected to the packet core network 2. The case where it communicates with the communication destination terminal (CN) Correspondent Node (CN) 3b to which it communicates is illustrated.

A home agent (HA) 21 is installed on the packet core network 2, and the home agent 21 is a care address (CoA) existing in addition to the home address and the home link of the mobile terminal device. Holds corresponding information (binding information), and manages the home address and the care-of address of each mobile terminal device MN. When the mobile terminal apparatus MN moves to a link other than the home link, the mobile terminal apparatus MN acquires a referral address from the link of the moving destination, and the mobile terminal apparatus registers the position with the home agent 21 with respect to the acquired referral address. In the example shown in Fig. 14, the wireless LAN 4 moves to the cellular packet network 6, and the care-of address is updated from CoA1 to CoA2.

Here, in the general mobile terminal apparatus in the above-mentioned IP mobility, as shown in FIG. 16, the address control unit 91 conceals a trusted address for each application 99 executed on the mobile terminal apparatus. The application of the mobile terminal apparatus communicates using the home address without using the care-of address. Hereinafter, the procedure of transmitting and receiving a packet between the mobile terminal device 3a and the communication destination terminal device 3b without using a request address in the application layer of the mobile terminal device will be described. 15 is an explanatory diagram showing transmission and reception of a conventional packet.

First, as shown in FIG. 15, when the data D11 is transmitted from the mobile terminal device 3a to the communication destination terminal device 3b, the mobile terminal device 3a is located at the head of the data D11. The header D12 addressed to the home address HoA of (3b) and the IP header D13 addressed to the home agent 21 are added (encapsulated) and transmitted. The home agent 21 captures the packet D1 addressed to the home agent 21, removes (decapsulates) the IP header D13 attached to the head, and decodes the communication destination terminal device 3b from the header D12. The home address HoA is obtained and transmitted to the corresponding HoA.

On the other hand, when the data D21 is transmitted from the communication destination terminal device 3b to the mobile terminal device 3a, the communication destination terminal device 3b transmits the packet D2 addressed to the home address of the mobile terminal device 3a. do. The home agent 21 captures the packet D2 addressed to the home address of the mobile terminal 3a, and adds an IP header D23 addressed to CoA corresponding to the home address of the mobile terminal 3a. Encapsulate and transmit the packet D2. When the mobile terminal device 3a receives the packet D2 addressed to the CoA, it first removes (decapsulates) the added IP header D23 to restore the original packet D21.

However, the IP mobility function has a problem that it is difficult to maintain the quality of real-time (RT) communication due to problems such as traffic concentration to the home agent 21. In detail, since the IP mobility function is that all communication is via a so-called MIP virtual interface through the home agent 21, communication paths are lengthened, communication delays occur, or packet loss due to load concentration on the home agent. This can cause deterioration of quality for UDP (User Datagram Protocol) based RT communication.

For this reason, even if MIP is used simply, the quality of TCP communication and UDP communication cannot be satisfied simultaneously. In the future, the mobile communication holding multiple communication sessions is more likely to be more realistic due to the wider access network and higher performance of the terminal. Therefore, a method of simultaneously maintaining the quality of TCP and RT communication is required.

Patent Document 1: Japanese Patent Application Publication No. 2005-340982

[Initiation of invention]

Thus, the present invention solves the above problems, and makes it possible to separate the interface between the IP mobility function and the real-time communication function of the mobile terminal device in mobile communication, and according to the QoS status of the real-time communication in the mobile terminal device. An object of the present invention is to provide a session control system, a session control method, and a mobile terminal device capable of simultaneously realizing TCP communication and maintaining quality of real-time communication by performing dynamic session control.

In order to solve the above problems, the present invention utilizes a mobile terminal device capable of communicating while moving on a communication network, and a fixed address that does not depend on the position of the mobile terminal device assigned to each mobile terminal device and a care-of address changed according to the position. The present invention relates to a session control system, a session control method, and a mobile terminal apparatus for performing communication using a home agent for relaying communication.

Specifically, in the present invention, the mobile terminal apparatus includes an application execution unit for executing an application for transmitting and receiving data, a communication quality monitoring unit for detecting a communication quality of a communication network, and a type of application executed in the application execution unit. And an address control unit for providing one or both of a fixed address and a care-of address to the application as a reception address in the transmission and reception of data in accordance with the detection result by the communication quality monitoring unit. This address control unit has a function of setting a communication path via the home agent when a fixed address is selected as the reception address, and selecting a communication path not via the home agent when the care address is selected.

And in the present invention,

(1) A mobile terminal apparatus, which executes an application that transmits and receives data, detects a communication quality of a communication network in the mobile terminal apparatus,

(2) Depending on the type of application executed on the mobile terminal device by the mobile terminal device and the detection result of the communication quality, one or both of a fixed address and a care-of address are provided to the application as a reception address in the transmission and reception of data. To do it,

(3) In (2), the communication path via the home agent is set when the fixed address is selected as the reception address, and the communication path not via the home agent is selected when the care address is selected.

According to the present invention, since the fixed address HoA and the care-of address CoA are switched in accordance with the communication quality (QoS state) of the communication network, the home agent in real-time communication is appropriately used by using the care address. It is possible to avoid traffic concentration on the network and to maintain a communication service cut by an address change such as TCP communication.

In the above invention, the mobile terminal device notifies the call control device on the communication network of the communication quality detected by the communication quality monitoring unit, and the call control device calls the call of the mobile terminal device according to the communication quality notified from the mobile terminal device. The control unit is instructed to optimize the communication path, and the call control unit of the mobile terminal device preferably selects whether to pass through the home agent according to the instruction of the call control device. In this case, the call control device is led to control based on the communication quality of both terminals related to the communication, and the communication path can be selected more appropriately.

In the above invention, the mobile terminal device notifies the call control device on the communication network of the communication quality detected by the communication quality monitoring unit, and the call control device corresponds to each terminal related to the communication according to the communication quality notified from the mobile terminal device. It is preferable to instruct the optimization of the coding band in the communication, and each mobile terminal device to perform the optimization of the coding band in accordance with the instruction of the call control device.

In this case, the call control device is led to control the coding band based on the communication quality of both terminals involved in the communication, and the communication state of both the transmission and reception by optimizing the traffic amount in parallel with the selection of the communication path described above. Depending on the traffic load can be adjusted step by step.

In the above invention, the mobile terminal device notifies the call control device on the communication network of the communication quality detected by the communication quality monitoring unit, and the call control device corresponds to each terminal related to the communication according to the communication quality notified from the mobile terminal device. It is preferable to instruct the optimization of the packet transmission interval in the communication, and the mobile terminal apparatus to optimize the packet transmission interval in accordance with the instruction of the call control apparatus.

In this case, the call control device is led to control the packet transmission interval based on the communication quality of both terminals involved in the communication, and to optimize the traffic amount in parallel with the above-described communication path selection, Traffic load can be adjusted step by step according to the communication status.

In the above invention, each optimization process may be executed by the mobile terminal apparatus. That is, in (1), the mobile terminal apparatus performs various optimization processing on the call control apparatus and the mobile terminal apparatus on the communication network according to the communication quality detected on the mobile terminal apparatus side (optimization and encoding of communication paths). Band optimization, packet transmission interval optimization), and in (3), each communication terminal apparatus cooperates with the mobile terminal apparatus and the call control apparatus of the communication partner to perform optimization processing according to the instruction of the mobile terminal apparatus. Run

In this case, on the basis of the communication quality of both terminals involved in the communication, various optimization processes led by one of the respective mobile terminal devices involved in the communication are enabled, and the traffic load is adjusted step by step without increasing the burden on the call control device. Can be.

BRIEF DESCRIPTION OF THE DRAWINGS It is explanatory drawing which shows schematic structure of the session control system which concerns on embodiment.

2 is a block diagram showing the configuration of the call control device according to the embodiment.

3 is a block diagram showing the configuration of a mobile terminal apparatus according to the embodiment.

4 is an explanatory diagram schematically showing a relationship between functional blocks of a mobile terminal device according to the embodiment.

5 is an explanatory diagram showing a procedure of optimization processing in the session control system according to the embodiment.

6 is an explanatory diagram showing a procedure of packet transmission and reception in the session control system according to the embodiment.

It is explanatory drawing which shows typically the operation of the session control system which concerns on embodiment.

8 is a flowchart showing the procedure of control of change of media attribute and optimization of communication path according to the embodiment.

9 is a flowchart showing the operation of the mobile terminal apparatus according to the embodiment.

10 is a flowchart showing the operation of the mobile terminal apparatus according to the embodiment.

11 is a flowchart showing the operation of the call control device according to the embodiment.

12 is a flowchart illustrating the operation of the call control device according to the embodiment, which is the continuation of FIG. 11.

FIG. 13 is a flowchart showing the operation of the call control device according to the embodiment;

It is explanatory drawing which shows schematic structure of the conventional session control system.

15 is an explanatory diagram showing a procedure of packet transmission and reception in a conventional session control system.

16 is an explanatory diagram schematically showing a relationship between functional blocks in a conventional mobile terminal apparatus.

Best Mode for Carrying Out the Invention

(Configuration of Session Control System)

Embodiments of the present invention will be described with reference to the drawings. 1 is an explanatory diagram showing a schematic configuration of a session control system according to the present embodiment.

In the session control system according to the present embodiment, as shown in FIG. 1, a call control device 1 such as a SIP (Session Initiation Protocol) server device is provided, and a core (nucleus) that performs voice communication by a packet-switched method. The cellular packet network 6 which communicates by the packet switching method between the packet core network (IP network) 2 and the mobile terminal devices 3a, such as a mobile telephone, which is connected to each other via the router apparatus 7, At the same time, the packet core network 2 and the wireless LAN 4 (WLAN: Wireless Local Area Network) for performing voice communication by the packet switching scheme are connected to each other via the router apparatus 7.

In the packet core network 2, an IP telephone network 8 or a public switched telephone network (PSTN) 9 capable of voice communication, in addition to a cellular network or a wireless LAN 4 as another communication network, includes a gateway device ( 5) or via the router apparatus 7. In addition, the gateway device 5 according to the present embodiment can be constituted by a media gateway controller (MGC), a signaling gateway (SG), a media gateway (MGW), and the like. Usually, MGC understands SIP and MGC understands SG. And MGW, and it is preferable to perform signaling and line connection, respectively.

In addition, the home agent 21 is provided in the packet core network 2. The home agent 21 holds and manages corresponding information (binding information) between the home address HoA and the care-of address CoA of the mobile terminal apparatus 3a. When the mobile terminal apparatus moves to a link other than the home link, the mobile terminal apparatus acquires a care-of address from the link of the moving destination, and the mobile terminal apparatus registers the position with the home agent 21 with respect to the acquired CoA.

(Configuration of call control device)

2 is a block diagram showing the configuration of a call control device according to the present embodiment. As shown in the same figure, the call control apparatus 1 is provided with the position registration processing part 103, the call control part 104, and the network (I / F) 105 as a function of a call control system.

The call control unit 104 transmits and receives a call control message with the mobile terminal device 3a and transmits the call control message to the communication destination terminal device 3b or the like serving as a destination. This module performs processing. The position registration processing unit 103 is a module for storing and updating the registration server upon receiving the position registration message from the call control unit 104. The position registration processor 103 holds CoA as well as HoA of each terminal as position information. The network interface 105 is a module including a physical network interface and a network control function such as a device driver and a dial-up function corresponding to the physical network interface and a basic protocol stack (such as TCP / UDP / IP).

In addition, the call control device 1 has a QoS management unit 102 and a 3PCC (3rd Party Call Control) unit 101. When the QoS management unit 102 receives a QoS related signal (alarm signal, quality reset signal, quality good signal, etc.) from the call control unit 104, it updates the connection state record corresponding to the registration data server 15. When this record is updated, the 3PCC unit 101 performs codec change or path optimization control from the QoS management unit 102 to the 3PCC unit 101 in accordance with the signal state where the signal generation time is recorded and received within a predetermined time. Instruct on. In addition, the 3PCC unit 101 is a module for changing the codec or packet transmission interval or performing path optimization with respect to a specified terminal device group using the order of 3PCC according to the instruction of the QoS management unit 102.

The call control device 1 further includes a registration data server 15 for storing the positional information and the connection state of each user, and a position registration processing unit 103 for performing the position registration processing for each user. The location information is data relating to HoA and CoA, which are standby storage addresses which are generally registered with an ID (telephone number, SIP-URI, etc.) identifying a client, and the connection status is an ID for identifying a connection completion call, and communication with each other. The data includes a group of client IDs, a codec in use, a codec priority, a call waiting storage address group (CoA / HoA), a QoS signal transmission source, and a reception time thereof.

In the call control device 1, the call control unit 104 registers and controls the connection state information indicating the connection state of each user to the registration data server 15 and simultaneously transmits the position information of each user to the position registration processing unit 103. send. When the location information is transmitted from the call control unit 104, the location registration processing unit 103 compares the transmitted location information with the location information registered in the registration data server 15, so that the user (mobile terminal device 3a) If it is determined that the communication network (currently, the accessing network) has been moved, the location information or the connection status of the mobile terminal device is updated.

(Composition of mobile terminal device)

FIG. 3 is a block diagram showing the configuration of the mobile terminal apparatus according to the present embodiment, and FIG. 4 is an explanatory diagram schematically showing the relationship between the functional blocks in the block diagram shown in FIG. As shown in Fig. 3, the mobile terminal device 3a (and the communication destination terminal device 3b) includes an application execution unit 39, a user interface 36, a network selection switching unit 33, and a network interface 311 to 311. 31n).

The application execution unit 39 is an arithmetic processing unit that executes various application software, and is composed of a TCP execution unit 39a for executing a TCP application and an RT execution unit 39b for executing a real-time application. Application software executed by the TCP execution unit 39a includes communication applications based on TCP such as a web browser, file transfer software, mailer software, and the like. The communication by this application execution unit 39 is connected to the TCP interface 32a via the socket interface 32, and from this TCP interface 32a, the MIP unit 31a and the network selection switching unit of the address control unit 31. It connects to the communication networks 311-31n via 33.

On the other hand, application software executed by the RT execution unit 39b includes UDP-based applications such as a SIP-based call application. Communication by this RT execution part 39b is connected to the UDP interface 32b via the socket interface 32, and from this UDP interface 32b, the MIP part 31a or the IP part 31b of the address control part 31 is carried out. ), And is connected to the network interfaces 311 to 31n through the network selection switching unit 33.

Specifically, the RT execution unit 39b includes a codec processing unit 37, a media transmission / reception unit 35, a quality monitoring unit 38, a call control unit 34, and an address control unit 31. The media transmission / reception unit 35 is a module for transmitting and receiving real-time data such as voice and moving pictures between the terminal devices 3b of the communication partner. The quality monitoring unit 38 monitors the QoS of real-time communication. The module transmits an alarm to the call controller when it is determined that the QoS is lowered compared to the set threshold. Here, the QoS value includes an average jitter of the communication packet, a packet loss rate, an average round trip delay time, and the like.

The call control unit 34 is a module that transmits and receives a call control message between the call control device 1 or the terminal device 3b of a communication partner, and performs media negotiation such as registration, call, call processing, and voice codec. In the present embodiment, the call control unit 34 performs dynamic codec change or reception address change according to the instruction of the call control device 1.

In addition, as shown in Fig. 4, the address control unit 31 is used as a reception address in the transmission and reception of data in accordance with the type of the application executed in the application execution unit 39 and the detection result by the quality monitoring unit 38. A module that selectively provides either or both of HoA and CoA to an application, and comprises a MIP unit 31a for performing communication using HoA and an IP unit 31b for performing communication using CoA. The MIP unit 31a is a module that performs normal MIP processing such as location registration and IP / UDP encapsulation for the home agent 21. In general, when this MIP process is executed, only the IF of the MIP can be used from the application. However, in the present embodiment, the MIP section 31a and the IP section 31b are separated from the UDP interface 32b, and Depending on the situation, MIP communication or non-MIP communication is selectively made available.

Further, the address control unit 31 determines the communication path via the home agent 21 when the HoA is used as the reception address in the terminal apparatus 3a, and the home agent 21 when the CoA is used. It has a function of establishing a communication path without passing through).

The network selection switching unit 33 is a module for monitoring the plurality of network interfaces 311 to 31n and selecting and connecting an optimum I / F from the user's preference, price, communication quality (field strength), and the like. The network selection switching unit 33 also functions to validate a plurality of I / Fs simultaneously for handover and to instruct the MIP unit 31a or the call control unit 34 to execute the position registration process. Also have.

The network interfaces 311 through 31n include a network control function (NCU) such as a physical network interface, a device driver and a dial-up function corresponding to the physical network interface, and a basic protocol stack (TCP / UDP / IP, etc.). .

The user interface 36 is a module including an input / output device including a voice card, a driver, a software interface, an AD / DA conversion unit, etc., to which a microphone, a speaker unit, or the like is connected. The codec processing unit 37 is a module for converting (codec conversion processing) the data transmitted from the user interface 36 or the media transmission / reception unit 35 into a format suitable for a corresponding module or communication partner.

(Optimization process)

In this embodiment, when each terminal monitors its own communication quality by the system having the above-described configuration and fails to satisfy a certain quality, the call control device 1 notifies the QoS related signal and calls control. The apparatus 1 grasps the communication quality of each terminal apparatus and performs stepwise by appropriately combining various optimization processes according to the signal conditions received from each terminal apparatus communicating with each other within a predetermined time.

(a) Receive alarm from one terminal → Optimization by changing media properties

(b) Receive alarm from both terminals⇒Route optimization

Specifically, first, in the media attribute change of (a), a decrease in the communication quality of the access network to which one of the terminals belongs, and the call control device 1 changes the packet transmission interval to the terminal or changes the low bandwidth codec. Instruct changes dynamically. In the path optimization of (b), assuming an overload state of the home agent 21, the MIP communication using HoA and the non-MIP communication using CoA are dynamically switched.

Further, when the session control of one of the above (a) and (b) is received and a quality alarm is received from a group of terminals related to the communication, the other control is performed and the quality of the RT communication is maintained. On the other hand, TCP communication which continues to use HoA can be simultaneously maintained by the mobility of MIP. On the other hand, the two session control in the proposed scheme is realized by combining the standard SIP mobility that can dynamically change the communication media attributes or IP address, and the SIP-3PCC sequence that can be controlled by a third party.

Specifically, the above-described various optimization processes are performed as follows. That is, as shown in FIG.

(1) Register both CoA and HoA of the mobile terminal device 3a in the call control device 1,

(2) When the mobile terminal apparatus 3a or 3b detects the QoS deterioration of RT communication, it notifies the call control apparatus 1 as a QoS related signal.

(3) The call control device 1 performs communication path optimization control (change to non-MIP) and optimization (media code change control and packet transmission interval control) by media attribute change by the notification state from the mobile terminal device. Do it,

(4) When the QoS is good, the call control device 1 performs control of raising the bandwidth of the codec or returning to MIP communication.

As such an optimization control of the communication path, when the data D11 is transmitted from the mobile terminal device 3a to the communication destination terminal device 3b as shown in Fig. 6, the mobile terminal device 3a is configured to store the data D11. At the beginning, the header D12 addressed to the home address HoA of the communication destination terminal apparatus 3b and the IP header D13 addressed to the home agent 21 are added (encapsulated) and transmitted. The home agent 21 captures the packet D1 addressed to the home agent 21, removes (decapsulates) the IP header D13 attached to the head, and decodes the communication destination terminal device 3b from the header D12. The home address HoA is obtained and transmitted to the corresponding HoA.

On the other hand, when the data D21 is transmitted from the communication destination terminal device 3b to the mobile terminal device 3a, the communication destination terminal device 3b transmits the packet D2 addressed to the home address of the mobile terminal device 3a. do. The home agent 21 captures the packet D2 addressed to the home address of the mobile terminal 3a, and adds an IP header D23 addressed to CoA corresponding to the home address of the mobile terminal 3a. Encapsulate and transmit the packet D2. When the mobile terminal 3a receives the packet D2 addressed to the CoA, the mobile terminal 3a removes (decapsulates) the added IP header D23 and restores the original packet.

On the other hand, in UDP-based communication, as shown in the packets D3 and D4, the headers D32 and D42 addressed to the care of address are added directly from both the mobile terminal apparatus 3a and the communication terminal terminal apparatus 3b. Data transmission and reception are performed. Thereby, as shown in (4) of FIG. 5, the communication path which does not pass through the home agent 21 (for example, via the router 42) is formed, and the addition concentration in the home agent 21 is concentrated. Can be avoided. As a result, the mobile terminal apparatuses 3a and 3b can simultaneously perform MIP communication and non-MIP communication, and the call control apparatus 1 grasps two destination addresses HoA and CoA of each terminal.

(Session control method)

The session control method of the present invention can be implemented by operating a session control system having the above configuration. 7 is an explanatory diagram schematically showing session control by the session control system according to the present embodiment.

In Fig. 7, first, both HoA and CoA are registered with the call control device 1 from the mobile terminal device 3a (f1). Subsequently, at the start of communication, the TCP execution unit 39a and the RT execution unit 39b of the mobile terminal apparatus 3a perform MIP communication using HoA (f2).

When the quality of the RT communication is lower than or equal to a certain quality, the mobile terminal apparatus 3a uses the INFO method (reference document "The SIP INFO Meshod", RFC2976, October, 2000), for example, to call control apparatus 1. Send a quality alarm signal to (f3). When the call control device 1 receives alarms from both terminals communicating with each other within a predetermined time, as shown in Fig. 5, the call control device 1 performs path optimization control using 3PCC (f4).

After that, when the quality alarm signal is received from the communication destination terminal device 3b side again (f5), media attributes such as a codec and a packet transmission interval used by the terminal are changed (f6). On the other hand, the TCP communication is maintained by the MIP by continuing to use the HoA (f7).

The procedure of control of media attribute change and optimization of the communication path in this embodiment will be described. Fig. 8A is a flowchart showing operations in media attribute change control, and (b) is a flowchart showing operations in communication path optimization control. In addition, although the case where codec is changed as change control of a media attribute is illustrated in FIG. 8A, the operation | movement at the time of a packet sending interval is also the same.

As shown in Fig. 8A, it is assumed that MIP or non-MIP communication is performed between the mobile terminal devices 3a and 3b (S401). For example, when an inquiry of codec (or packet transmission interval) designation is made from the call control device 1 to the mobile terminal device 3a side (S402), the mobile terminal device 3a designates this. In accordance with this, a reception address and a port are specified (S403). The call control device 1 makes an inquiry of codec designation to the communication destination terminal device 3b in order to notify the communication destination terminal device 3b of the reception address and port designated by the mobile terminal device 3a ( In step S404, the communication destination terminal apparatus 3b designates its reception address and port (S405).

The call control device 1 notifies the mobile station apparatus 3a of the reception address and port of the communication destination terminal apparatus 3b as an ACK (S406), and when communication with the mobile terminal apparatus 3a is established. An ACK is transmitted to the communication destination terminal device 3b (S407).

In addition, as shown in Fig. 8 (b), when the communication using HoA (MIP communication) is performed between the mobile terminal devices 3a and 3b, the corresponding MIP communication is switched to communication by CoA (non-MIP communication). For example, when an inquiry of non-MIP communication is performed from the call control device 1 to the mobile terminal device 3a (S502), the mobile terminal device 3a responds to the request address and port according to this designation. Is specified (S503). The call control device 1 inquires the non-MIP communication of the communication destination terminal device 3b to notify the communication destination terminal device 3b of the request address and port designated by the mobile terminal device 3a. (S504), the communication destination terminal device 3b designates its own home address and port (S505). In the case where the path optimization is also performed with respect to the communication destination terminal device 3b at the same time, this step S505 is also performed on the communication destination terminal device 3b side. You can specify the CoA and port in.

The call control device 1 notifies the mobile terminal apparatus 3a of the home address and port of the communication destination terminal apparatus 3b as an ACK (S506), and when communication with the mobile terminal apparatus 3a is established. An ACK is transmitted to the communication destination terminal device 3b (S507).

Next, in the above-described session control, specific operations in the mobile terminal apparatus and the call control apparatus will be described. 9 and 10 are flowcharts of operations at the mobile terminal apparatus 3a side.

First, the communication quality is monitored on the mobile terminal device side. Specifically, as shown in Fig. 9, the mobile terminal 3a periodically inquires of the QoS information to the media transceiver 35 (S101), and monitors whether or not QoS falls below the lower limit threshold. (S102). If the QoS falls below the lower limit threshold ("Yes" in S102), the call controller 1 is instructed to transmit the quality alarm signal (S103).

On the other hand, if it is determined in step S102 that the QoS is equal to or higher than the lower limit threshold ("No" in S102), then it is monitored whether the QoS is lower than the upper limit threshold (S104). If the QoS is lower than the upper limit threshold (Yes in S104), the call controller 1 is instructed to transmit the quality reset signal (S105). If it is determined in step S104 that the QoS exceeds the upper limit threshold ("No" and S106 in S104), the call control device 1 is instructed to transmit a quality good signal (S107).

In this way, in accordance with the QoS related signal transmitted from the mobile terminal apparatus to the call control apparatus 1, the call control apparatus 1 leads and performs each optimization process. At this time, when the mobile terminal apparatus receives a change request for a call during communication by MIP as shown in Fig. 10 (S201 and S202), it is determined whether the change request is a change request for a codec ( S203). In the case of a codec change request (YES in S203), the media transmission / reception unit 35 is notified of the codec change, a new data receiving port number is obtained (S204), the current data receiving address HoA and the new port. The number is returned (S205). Thereafter, the media transmission / reception unit 35 notifies the data transmission destination address and the port number included in the ACK (S206).

If it is determined in step S203 that the change request is not a codec change request ("No" in S203), it is judged whether or not the content of the change request is a path change request (S207). If it is not a route change request, the flow returns to step S201 to be in a wait state until the next change request is received.

If it is determined in step S207 that the path change request is made, the media transmission / reception unit 35 is notified of the path change, and a new data reception port number at the new care-of address (CoA) is obtained (S208), and the new data reception address is received. (CoA) and the new port number are returned (S209). Thereafter, the media transmission / reception unit 35 notifies the data transmission destination address and the port number included in the ACK (S210).

11 to 13 are flowcharts of the operation on the call control device 1 side. If the QoS related signal is received from the call controller 104 while waiting (S301 and S302), the registration data server 15 is instructed to read the connection state record for the corresponding terminal (S303), and the received signal is a quality alarm signal. It is determined whether or not the recognition (S304).

In step S304, if the received signal is a quality alarm signal (" Yes " in S304), it is judged whether or not the corresponding communication partner is in the alarm set state (S305). Optimization control for switching the path to non-MIP communication is instructed to the 3PCC unit 101 (S306). In step S305, when the communication partner is not in the alarm set state ("No" in S305), the terminal alarm state of the corresponding record is set to instruct the registration data server 15 to update (S310). A timer event relating to the program is set (S311) and the state is transferred to the waiting state (S301).

On the other hand, when it is determined in step S304 that the received signal is not a quality alarm signal ("No" in S304), it is determined whether or not the received signal is a quality reset signal (S307). When the received signal is a quality reset signal, the registration data server 15 is instructed to read out a connection state record for the terminal (S308), resets the alarm state for the terminal of the record (S309), and returns to the standby state. Go (S301).

On the other hand, if it is determined in step S307 that the received signal is not a quality reset signal ("No" in S307), the received signal is registered as a quality good signal (S318) to read out a connection state record for the terminal. The data server 15 is instructed (S319), and it is judged whether or not the communication partner has a good quality set state (S320). When the quality is in the good set state (Yes in S320), the 3PCC unit 101 is instructed to change control to MIP communication for the communication (S321), and the state goes to the standby state (S301). In step S320, when the communication partner is not in the good quality set state ("No" in S320), the corresponding terminal quality good state of the record is set, and the registration data server 15 is instructed to update (S322). The timer event for the record is set (S323), and the state transitions to the waiting state (S301).

When the timer event is received in the waiting state S301 (S312), the registered data server 15 is instructed to read the timer set connection state record (S313). Thereafter, it is determined whether one of the terminals related to the communication is in the alarm set state (S314), and when it is in the alarm set state ("Yes" in S314), the codec change (band reduction) for the corresponding communication is made. The 3PCC unit 101 is instructed (S315). On the other hand, when it is determined in step S314 that neither terminal is in the alarm set state ("No" in S314), it is judged whether one terminal is in a good quality state and the other terminal is in an alarm reset state. (S316) In this case ("Yes" in S316), the 3PCC unit 101 is instructed to change the codec (band increase) for the corresponding communication (S317). On the other hand, in step S316, when either terminal is not in the quality good state and the alarm reset state, the state transitions to the standby state (S301).

(Action, effect)

According to the present embodiment described above, since the HoA and the CoA are switched according to the communication quality (QoS state) of the communication network, UDP communication using a caretaker address can be performed appropriately, and the home agent in real-time communication can be used. It is possible to avoid traffic concentration and maintain communication services such as TCP communication.

In addition, in this embodiment, since the call control device performs various optimizations based on QoS-related signals from each mobile terminal device, the communication quality of both communication terminal devices (for example, 3a and 3b) related to the communication is performed. Control is possible, more appropriate communication path selection, coding band control, and packet transmission interval can be controlled, and traffic load can be adjusted step by step according to the communication status of both transmission and reception.

As a result, according to this embodiment, dynamic session control based on QoS is enabled by the call controller (SIP server) 1 using, for example, mobility of SIP and 3PCC order in a multi-access network environment, and MIP. It is possible to realize the continuous TCP communication and the RT communication quality.

(Change example)

In addition, this invention is not limited to embodiment mentioned above, A various change can be added. For example, in the above embodiment, each optimization process is led and executed by the call control device 1, but for example, each mobile terminal device 3a or 3b related to communication may be led. That is, the mobile terminal apparatus 3a or 3b detects the communication quality and judges the communication quality detected on the mobile terminal apparatus side, and according to the determination result, the call control apparatus 1 and the mobile terminal apparatus of the communication partner. May be directed to various optimization processes (optimization of communication path, optimization of coding band, optimization of packet transmission interval). In this case, the call control unit of each communication terminal device executes the optimization process in accordance with the instructions from the mobile terminal device which is led in cooperation with the mobile terminal device and the call control device 1 of the communication partner.

According to this modification, the traffic quality can be adjusted step by step without increasing the burden on the call control device 1 because the quality of the communication is detected by one of the respective mobile terminal devices involved in the communication, and the good and the bad are judged.

As described above, according to the present invention, in the mobile communication, the interface between the IP mobility function and the real-time communication function of the mobile terminal device is separated, and the mobile terminal device performs dynamic session control according to the QoS state of the real-time communication. Therefore, it is possible to simultaneously maintain the TCP communication and maintain the quality of the real-time communication.

Claims (21)

A mobile terminal device capable of communicating while moving on a communication network, A session control system having a home agent for relaying communication using a fixed address that does not depend on the position of the mobile terminal device assigned to each mobile terminal device and a care-of address changed according to the position, The mobile terminal device, An application execution unit that executes an application that transmits and receives data, and A communication quality monitoring unit detecting a communication quality of the communication network; Depending on the type of application executed by the application execution unit and the detection result by the communication quality monitoring unit, one or both of the fixed address and the care-of address as the reception address in the transmission / reception of the data may be assigned to the application. An address control unit for providing the The address control unit, Has a function of setting a communication path via the home agent when the fixed address is selected as the reception address, and selecting a communication path not via the home agent when the care address is selected; Session control system. The method of claim 1, On the communication network, a call control device for instructing optimization of a communication path is provided in a call control unit of each mobile terminal device related to the communication in accordance with the communication quality notified from the mobile terminal device. The mobile terminal device has a function of notifying the call control device of the communication quality detected by the communication quality monitoring unit, And a call control unit of the mobile terminal device having a function of selecting whether or not to pass through the home agent to the address control unit according to the instruction from the call control device. The method of claim 1, On the communication network, a call control device for instructing optimization of the coding band in the communication is provided in each terminal related to the communication in accordance with the communication quality notified from the mobile terminal device. The mobile terminal device has a function of notifying the call control device of the communication quality detected by the communication quality monitoring unit, And each terminal related to the communication has a function of optimizing the coding band in accordance with the instruction from the call control device. The method of claim 1, On the communication network, a call control device instructing each terminal related to the communication to optimize the transmission interval of packets in the communication according to the communication quality notified from the mobile terminal device, The mobile terminal device has a function of notifying the call control device of the communication quality detected by the communication quality monitoring unit, And each terminal related to the communication has a function of optimizing a transmission interval of the packet in accordance with the instruction from the call control device. The method of claim 1, The mobile terminal device has a call control unit for instructing the call control device on the communication network and the mobile terminal device of the communication partner to optimize the communication path according to the communication quality detected by the communication quality monitoring unit. The mobile terminal apparatus and the call control apparatus of the communication partner have a function of selecting whether or not to pass through the home agent to the address control unit according to the instruction from the call control unit. The method of claim 1, The mobile terminal device has a call control unit for instructing the call control device on the communication network and the mobile terminal device of the communication partner to optimize the coding band in the communication according to the communication quality detected by the communication quality monitoring unit. And said call control device having said communication partner has a function of optimizing said coding band in accordance with said instruction from said call control unit. The method of claim 1, The mobile terminal device has a call control unit for instructing the call control device on the communication network and the mobile terminal device of the communication partner to optimize the encoding band in the communication according to the communication quality detected by the communication quality monitoring unit. And the call control device having the communication partner has a function of optimizing the transmission interval of the packet in accordance with the instruction from the call control unit. A mobile terminal device capable of communicating while moving on a communication network, A session control method for performing communication by using a home agent that relays communication by a fixed address that does not depend on the position of the mobile terminal device assigned to each mobile terminal device and a care-of address changed according to the position, A step (1) of executing the application for transmitting and receiving data in the mobile terminal device and detecting the communication quality of the communication network in the mobile terminal device; Depending on the type of application executed on the mobile terminal device by the mobile terminal device and the detection result of the communication quality, any one or both of the fixed address and the care-of address as the reception address in the transmission / reception of the data may be selected. Step (2) to be provided to the application, In the step (2), a communication path via the home agent is set when the fixed address is selected as the reception address, and a communication path not via the home agent when the care address is selected. And a step (3) of selecting. The method of claim 8, In step (1), the mobile terminal device notifies the call control device on the communication network of the communication quality detected by the communication quality monitoring unit, and the call control device moves according to the communication quality notified from the mobile terminal device. Instructing the call control unit of the terminal device to optimize the communication path, And in the step (3), the call control unit of the mobile terminal apparatus selects whether to pass via a home agent according to the instruction from the call control apparatus. The method of claim 8, In step (1), the mobile terminal device notifies the call control device on the communication network of the communication quality detected by the communication quality monitoring unit, and the call control device responds according to the communication quality notified from the mobile terminal device. Instructing each terminal related to the communication to optimize the coding band in the corresponding communication; And in said step (3), said mobile terminal apparatus performs optimization of said coding band in accordance with said instruction from said call control apparatus. The method of claim 8, In step (1), the mobile terminal device notifies the call control device on the communication network of the communication quality detected by the communication quality monitoring unit, and the call control device according to the communication quality notified from the mobile terminal device. Instructing each terminal related to the optimization of the transmission interval of the packet in the corresponding communication, And in said step (3), said mobile terminal apparatus performs optimization of said packet transmission interval in accordance with said instruction from said call control apparatus. The method of claim 8, In the step (1), the mobile terminal device instructs the call control device on the communication network and the mobile terminal device of the communication partner to optimize the communication path according to the communication quality detected at the mobile terminal device side. In the step (3), the mobile terminal apparatus and the call control apparatus of the communication partner select whether or not to pass through the home agent according to the instruction from the mobile terminal apparatus. The method of claim 8, In the step (1), the mobile terminal device instructs the call control device on the communication network and the mobile terminal device of the communication partner to optimize the coding band in the communication according to the communication quality detected on the mobile terminal device side. , In said step (3), said mobile terminal apparatus and said call control apparatus of said communication partner perform optimization of said coding band in accordance with said instruction from said mobile terminal apparatus. The method of claim 8, In the step (1), the mobile terminal device instructs the call control device on the communication network and the mobile terminal device of the communication partner to optimize the coding band in the communication according to the communication quality detected by the communication quality monitoring unit. and, In said step (3), said communication terminal's mobile terminal apparatus and said call control apparatus perform optimization of the transmission interval of said packet in accordance with said instruction from said call control unit. A mobile terminal device capable of communicating while moving on a communication network, A mobile terminal device used as a session control system having a home agent for relaying communication using a fixed address that does not depend on the position of the mobile terminal device assigned to each mobile terminal device and a care-of address changed according to the position. as, An application execution unit that executes an application that transmits and receives data, and A communication quality monitoring unit detecting a communication quality of the communication network; Depending on the type of application executed by the application execution unit and the detection result by the communication quality monitoring unit, one or both of the fixed address and the care-of address as the reception address in the transmission / reception of the data may be assigned to the application. An address control unit for providing the The address control unit, Has a function of setting a communication path via the home agent when the fixed address is selected as the reception address, and selecting a communication path not via the home agent when the care address is selected; Mobile terminal device. The method of claim 15, A function of notifying the call control device on the communication network of the communication quality detected by the communication quality monitoring unit; And a call control section for selecting whether or not to pass through a home agent to the address control section in accordance with the instruction acquired from the call control device in accordance with the communication quality notified from the mobile communication device. The method of claim 15, A function of notifying the call control device on the communication network of the communication quality detected by the communication quality monitoring unit; And a function of optimizing the coding band in accordance with the instruction acquired from the call control device in accordance with the communication quality notified from the mobile terminal device. The method of claim 15, A function of notifying the call control device on the communication network of the communication quality detected by the communication quality monitoring unit; And a function for optimizing the sending interval of the packet in accordance with the instruction acquired from the call control device in accordance with the communication quality notified from the mobile terminal device. The method of claim 15, According to the communication quality detected by the communication quality monitoring unit, further comprising a call control unit for instructing the optimization of the communication path to the call control device on the communication network and the mobile terminal device of the communication partner, And the address control unit has a function of selecting whether or not to pass through the home agent in cooperation with a mobile communication device and a call control device of a communication partner. The method of claim 15, According to the communication quality detected by the communication quality monitoring unit, the call control device on the communication network and the mobile terminal device of the communication partner further has a call control unit for instructing the optimization of the coding band in the communication, And the address control unit has a function of optimizing the coding band in cooperation with the mobile terminal apparatus and the call control apparatus of the communication partner. The method of claim 15, According to the communication quality detected by the communication quality monitoring unit, the call control device on the communication network and the mobile terminal device of the communication partner further has a call control unit for instructing the optimization of the coding band in the communication, And the address control unit has a function of optimizing the transmission interval of the packet in cooperation with the mobile terminal apparatus and the call control apparatus of the communication partner.

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